Adubação fosfatada a lanço em culturas anuais sob sistema de semeadura direta

Abstract

Modern agriculture has tried to incorporate new technologies to reduce costs, optimize the workforce and achieve operational efficiency. In this context, early broadcast fertilization has been performed by a growing number of farmers and has been showed by researchers as a practicable alternative to improve the operational yield and help farmers to save resources. Although phosphorous (P) broadcast application on several annual crops on large farms has increased, there is a concern about this type of management regarding the low mobility of this nutrient on the soil and possible losses caused by precipitation with Fe+3, Al+3 e Mn+2, through formation of insoluble phosphates. On no-till farming system (SSD in Portuguese), there is a different behavior on the soil chemistry attributes, resulting in higher organic matter and nutrients concentrations in the upper layers. There is also concern with the direct contact of phosphorous with lime applied on surface, occasionally forming Calcium Phosphate, an unavailable form of this nutrient for plants. Thereby, this literature review aims to show and discuss current relevant aspects about the efficiency of broadcasted phosphorous fertilization and on surface of no-till farming areas. Some studies performed mainly on maize and soybean have shown the broadcast application on surface normally is more efficient on soils with appropriate P levels. However, the results found may indicate low crop yield, requiring new studies to verify the efficiency of this practice for high productivity levels.